Long Term Evolution (LTE) is a new network scheme recommended by the 3rd Generation Partnership Project (3GPP). In an LTE network, all communications are carried over an IP channel from user equipment (UE) to an all-IP core called the Evolved Packet Core (EPC). The EPC then provides gateway access to other networks while ensuring an acceptable Quality of Experience (QoE) and charging a subscriber for their particular network activity.
The 3GPP generally describes the components of the EPC and their interactions with each other in a number of technical specifications. Specifically, 3GPP TS 23.203, 3GPP TS 29.212, 3GPP TS 29.213, and 3GPP TS 29.214 describe the Policy and Charging Rules Function (PCRF), Policy and Charging Enforcement Function (PCEF), and Bearer Binding and Event Reporting Function (BBERF) of the EPC. These specifications further provide some guidance as to how these elements interact in order to provide reliable data services and charge subscribers for use thereof. The 3GPP specification allows the Policy and Charging Control (PCC) architecture to interwork with older generation networks (e.g., General Packet Radio Service (GPRS)). For example, 3GPP TS 29.212 and 3GPP TS 29.214 provide some guidance on the establishment of an application session by the EPC upon receipt of an application request from an Application Function (AF) in the form of an AA-Request (AAR) message or from a Packet Data Network Gateway (PGW) in the form of a Credit Control Request (CCR) message. The standards specify that the PCRF is responsible for receiving new service requests, creating new PCC rules commensurate with such requests, and providing these new PCC rules to a Policy and Charging Enforcement Function (PCEF) for installation. The 3GPP standards also define the format of service request messages and PCC rules.
The 3rd Generation Partnership Project (3GPP) Policy and Charging Control specifications provide a framework for authorizing Quality of Service (QoS) by Policy and Charging Rules Function (PCRF). These specifications provide QoS Negotiation and QoS Upgrade Attribute Value Pairs (AVPs) for negotiating and upgrading the QoS for General Packet Radio Service (GPRS) networks. The 3GPP specification suggests that the absence of QoS Negotiation AVP in the CCR indicates QoS negotiation supported and the absence of QoS Upgrade AVP in the CCR indicates QoS upgrade not supported. The 3GPP specifications are not complete and leave up to the reader the interpretation for implementation. For example, 3GPP specification does not specify if the QoS Negotiation and QoS Upgrade AVPs work in tandem or independently.
Therefore, a means of providing a deterministic way of calculating the authorized QoS is highly desirable.